Starting Engine Whilst On Ehu

[laneside]

This maybe another scare mongering urban myth or something specific to Rapido but I have just been reading the handbook and it states in big capitals a warning DO NOT START THE ENGINE WHEN ON MAINS HOOK UP. I never knew this and I bet many more do not but I am sure someone will be along soon to educate us

 

[Techno]

In case you drive away with the hook up post

 

[DavidG58]

My Hymer warns / reminds me if I am still connected, but I presumed this was to remove the risk of ripping the post out of the ground or the socket out of the MH

That said I have on a few occasions still been warned I am connected when I have definitely disconnected, I don't know if it is faulty or a function of the solar panel output

I do not have a substantiated technical answer but really cant see what harm could be done

 

[Mel]

The only problem I had when I did that was sparks from the cable when it left the plug in the Motorhome. Oops.

Mel

 

[Techno]

If a manual is going to make bold statements like that it should at least explain why even if the end user would not understand.
In fact if it is so critical there should be a means to prevent it happening (not everyone has or reads a manual)
Yesterday after pitching up I decided the van could go back another couple of feet, it didn't catch fire

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[TheBig1]

some battery chargers dislike a higher voltage fed back into them from the alternator

 

[old-mo]

I get a loud buzzer going off...

But as soon as I disconnect it stop`s...

 

[K9Brian]

Typical male - 3 years on and just getting round to reading the handbook

 

[laird of Dunstan]

It's probably due to the risk of two conflicting power supply and related to the earthing causing problems related to electrical/ electronic components opposing each other.
I may be wrong

 

[jonandshell]

Our van is left permanently on hookup at home.
I have a coiled lead (like a telephone handset lead) to avoid snagging.
I am shunting it back and forth quite often to gain access to our garage up and over door.
No problems to report!

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[SandT]

Technically its because if you are on EHU and the engine is running the electric 220/240 volts might meet the 12v
supply . Now this is the important bit ......

If they don't get on they might have a fight and the big electric will hit the little electric right in the googlies causing the little electric to run away and cry and you don't ever want water in your electrics!

Hope this helps.

Terry

 

[GJH]

some battery chargers dislike a higher voltage fed back into them from the alternator

It's probably due to the risk of two conflicting power supply and related to the earthing causing problems related to electrical/ electronic components opposing each other.
I may be wrong

I've read this in the past and that it is for reasons such as these. I think it differs between vans, though, depending on components used and how they are interconnected.

 

[jonandshell]

Look, lets look at this carefully and not perpetuate more internet myths, or in layman's terms, bollocks!

Built in charger is switched on. It applies voltage to your batteries.
You start your engine, the alternator applies voltage to your batteries.
Now, one of these, probably the alternator, will supply more voltage than the other. The provider of the lower voltage will cease to provide charge.
There is no conflict, sparks will not fly. 240v AC will NOT come into contact with your 12 volt system!

How many of you worry about disconnecting your solar before you start your van or connect the EHU lead?

 

[Gromett]

In General I would agree with jonandshell. However...
I have burnt out a charger by starting the engine with the EHU connected.
The charger was an el Cheapo, I had flat batteries and had connected the EHU to recharge the van battery. I gave it 20 minutes then started the van. It took some starting. I got a nasty smell from the back of the van and when I looked the Charger was smoking.

It appears the El cheapo charger had no thermal protection and for some reason the voltage regulation was confused by the nature of the load and gave it everything it had resulting in a burnt out transformer in the charger. Needless to say I have never bought an El Cheapo charger again.

 

[scotjimland]

not perpetuate more internet myths, or in layman's terms, bollocks!

spoilsport.. we love myths and bollox on Fun .. it's the lifeblood..

where would we be without a good gassing tale, or 20 car pile up on the M25 caused by a vanner dumping slippy grey water

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[peterc10]

spoilsport.. we love myths and bollox on Fun .. it's the lifeblood..

where would we be without a good gassing tale,

Haven't had one of those for a couple of weeks. Probably due one soon.

 

[Don Quixote]

This maybe another scare mongering urban myth or something specific to Rapido but I have just been reading the handbook and it states in big capitals a warning DO NOT START THE ENGINE WHEN ON MAINS HOOK UP. I never knew this and I bet many more do not but I am sure someone will be along soon to educate us

Alan, "DO NOT START THE ENGINE WHEN ON MAINS HOOK UP" because ???? - I would say CRAP manual and would be emailing Rapido asking WHY this is stated and WHY the reason was left out. By the way...... you are the first man I have come across who reads the manual all be it 1/2/3 years late.....

 

[DBK]

In General I would agree with jonandshell. However...
I have burnt out a charger by starting the engine with the EHU connected.
The charger was an el Cheapo, I had flat batteries and had connected the EHU to recharge the van battery. I gave it 20 minutes then started the van. It took some starting. I got a nasty smell from the back of the van and when I looked the Charger was smoking.

It appears the El cheapo charger had no thermal protection and for some reason the voltage regulation was confused by the nature of the load and gave it everything it had resulting in a burnt out transformer in the charger. Needless to say I have never bought an El Cheapo charger again.

My guess would be when you start the engine the starter battery voltage drops significantly for a short time as it starts cranking the engine. At this point the MH charger may produce too much current as it tries to maintain the engine battery voltage.

This doesn't mean the MH system will burn out every time, it may have overload protection and if the engine battery is in good condition the drop in voltage may not be severe - but it could happen.

 

[Judge Mental]

Please dont! You may well set of a cataclysmic chain of events that may hasten the end of the world!

 

[GWAYGWAY]

Haven't had one of those for a couple of weeks. Probably due one soon.

I thought about fitting a nitrous oxide power upping kit and fitting it in the living area instead as it would liven up the solemn atmosphere
I could then sell them to MH's and when they all passed out I could rob them for insurance purposes.
WILL THAT START IT OFF ????

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[GJH]

Please dont! You may well set of a cataclysmic chain of events that may hasten the end of the world!

He's already done that by moving to France. The Tod rain will follow sooner rather than later leading to irreversible climate change.

 

[pappajohn]

Look, lets look at this carefully and not perpetuate more internet myths, or in layman's terms, bollocks!

Built in charger is switched on. It applies voltage to your batteries.
You start your engine, the alternator applies voltage to your batteries.
Now, one of these, probably the alternator, will supply more voltage than the other. The provider of the lower voltage will cease to provide charge.
There is no conflict, sparks will not fly. 240v AC will NOT come into contact with your 12 volt system!

How many of you worry about disconnecting your solar before you start your van or connect the EHU lead?

At last....a factual and sensible answer.

 

[cruiser]

who wants facts. I was enjoying this. and I have never read my manual . and I have had mine 25 years.

 

[Sidney]

Yesterday after pitching up I decided the van could go back another couple of feet, it didn't catch fire

You got away with it again then... To think you didn't even switch off all the appliances, switch off the control panel and all MCBs and RCD nor disconnect the gas?

 

[Gromett]

Yesterday after pitching up I decided the van could go back another couple of feet, it didn't catch fire

I have seen the pictures of your electrical system. I am guessing most of us don't have such impressively wired/protected vehicles. Either that or you got lucky this time

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[eddie]

Look, lets look at this carefully and not perpetuate more internet myths, or in layman's terms, bollocks!

Built in charger is switched on. It applies voltage to your batteries.
You start your engine, the alternator applies voltage to your batteries.
Now, one of these, probably the alternator, will supply more voltage than the other. The provider of the lower voltage will cease to provide charge.
There is no conflict, sparks will not fly. 240v AC will NOT come into contact with your 12 volt system!

How many of you worry about disconnecting your solar before you start your van or connect the EHU lead?

I disagree with this post! It's NOT bollocks!

The expression is UTTER bollocks lol

Each device can only supply on need, no need, no supply

Jonandshell is ( as usual) 100% correct

 

[DanielFord]

I have to say, reading this, I was reminded of an incident last week. I was fitting a new stereo, and checking for the permanent live and switched live feeds. Anyway, long story short, I switched on ignition, and started the engine, and get the warning buzzer, fine, the step is probably out, I shall wait for it to retract I think. After about 30 seconds it dawns on me that something is not quite right. So I switch of the engine, and clean up all the contacts on the step, and this time hop in with the step retracted, start engine, once again I get the continuous buzzer! I am now totally confused, until I look in the mirror and see the hookup lead attached!
So apart from proving that I am a gigantic bellend, I don't think any harm comes from starting whilst hooked up!

 

[Tootles]

My Hymer wont start with the EHU plugged in. I don't know if it was built that way, but there is a hook up warning light on the interior control panel. Whilst that's lit, no starto.

 

[tonyidle]

I wish hook-up plugs would disconnect more easily. I'm sick of carrying my bungalow the length of the street every time it follows me out of the drive (which is looking very scuffed now).

 

[Tootles]

Yes, I

I wish hook-up plugs would disconnect more easily. I'm sick of carrying my bungalow the length of the street every time it follows me out of the drive (which is looking very scuffed now).

Yes, I passed your place last week.

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